1. Field of the Invention
The present invention relates to an image-capturing apparatus, an image-capturing method, and a computer program product, capable of obtaining position information.
2. Description of the Related Art
In recent years, widespread use of a portable GPS (Global Positioning System) receiver has lead to wider use of a GIS (Geographic Information Service) system utilizing position information. The GIS system is used in various fields in grasping the situation of disasters, handling real estate affairs, executing road works, and the like, thus expected to meet increasing market demands in future.
The GIS system often requires the use of a digital camera. For example, in the use of the GIS system for investigation of the situation of a disaster scene, the situation of a disaster-stricken area is photographed with a digital camera, and photographic data is associated with map data later to prepare a report or the like. In this manner, therefore, the GIS system brings a need of associating an image captured by the digital camera with information related to the image, such as photographing position information.
A technology that meets such a need is disclosed, for example, in Japanese Patent Application Laid-Open No. 2004-357343. According to the technology, a digital camera is connected to a GPS receiver, and position information from the GPS receiver is input to the digital camera, at which the position information (GPS information) is included in the header of a captured image. Through this technology, the position information of the captured image is recorded in the same image file containing the captured image, which achieves more efficient image management.
The GPS receiver, however, can usually be used only in the outdoor environment. This poses a problem, for example, that position information cannot be recorded in image data of the image photographed inside a building.
Moreover, photographing such a subject as tall building accompanying difficulty in photographing an overall view of the subject from a place close to the subject also poses a problem that the subject needs to be photographed from a place distant from the subject, so that exact position information of the subject cannot be recorded in image data when position information at the time of photographing is recorded in the image data.
Furthermore, recording direction information at the time of photographing in image data also poses a problem of a need of expensive equipment, such as an electronic compass.